Many disk drives used with data processing systems are designed to accept small size removable disk cartridges. Shown in FIG. 1 is a typical prior art removable disk cartridge 10 which includes an enclosure 11 having mating top an bottom casings 12 and 13. A disk 20 is rotatably mounted within the enclosure. The disk can be made of either a rigid or flexible storage media. The disk has at least one recording surface 22. A hub 21, externally accessible via a throughhole 23 in the disk cartridge, is for removably connecting to an external disk spindle of a disk drive to enable the disk to be rotated.
A door mechanism 14 provides access to the interior of the disk cartridge for the read/write head of the disk drive when the disk cartridge is inserted in the disk drive. The door mechanism is normally closed when the disk cartridge is removed from the disk drive to seal the interior of the disk cartridge from dust and other contaminants which otherwise could enter the interior of the disk cartridge and possibly damage the delicate recording surface of the disk.
Most prior art removable disk cartridges are designed for use with disk drives having the read/write head mounted at a free end of a linear actuator. During operation of the disk drive, the spindle rotates the disk, and the actuator positions the read/write head in a straight line path next to the recording surface of the disk.
It would be an advantage to design a removable disk cartridge adapted for use with a disk drive having a rotary actuator. A rotary actuator generally has a lower inertia than a linear actuator and can therefore position the read/write head faster to decrease seek latency. However, the rotary actuator positions the read/write along an arcuate path. It is a problem to provide a simple to assemble door mechanism which provides access for the read/write heads of disk drives having rotary actuators without interfering with the pivotal motion of the actuator and read/write head, during head loading and loading, and while the disk is in operation.
It would also be an advantage to have a disk cartridge which provides lateral access to the disk without interference by the enclosure. For example, most known cartridges have a portion of the enclosure, generally indicated by numeral 24 in FIG. 1, which partially obstructs lateral access to the disk. The arms of the actuator have to be especially designed to fit around this obstruction.
It also is a problem to effectively seal the disk cartridge in the general area of the throughhole 23 when the disk cartridge is removed from the disk drive. This is particularly true for disk cartridges which store data at higher recording densities, for example, data recorded with optical recording techniques. When data are recorded at higher densities, contamination on the recording surface is more likely to interfere with the correct operation of the cartridge.